I've come back for good?
I've came back for good?

These confuse me. When should I use come and when should I use came? could you give me an example?
Use come for the present tense (come, comes).
Use come after the auxiliary have (has, have, had, having).
Use came for the simple past (no auxiliary).

Is that clear enough?

I've come back for good.

I've means I have. After auxiliary have use the past participle, no matter what the verb. The past participle of come is come.

I came back for good.

Auxiliary have is not used here. came is the simple past tense of come.

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 CalifJim's reply was promoted to an answer.
Wow thank you for being so clear.